diff --git a/rtl/embedded/heapmgr.pp b/rtl/embedded/heapmgr.pp
index 50b597ecf6..060a9d92c1 100644
--- a/rtl/embedded/heapmgr.pp
+++ b/rtl/embedded/heapmgr.pp
@@ -195,6 +195,8 @@ Unit heapmgr;
             exit;
           end;
         sz := Align(FindSize(addr)+SizeOf(pointer), sizeof(pointer));
+        if sz < MinBlock then
+          sz := MinBlock;
 
         InternalFreeMem(@pptruint(addr)[-1], sz);